macOS desktop app runs with a ModuleNotFoundError(opencv / cv2) exception

[Xuu6770]

My project requires the opencv-python library, I have installed the dependency and the program runs and works fine.

But after I compile(I'm using PyCharm's own terminal to execute the command) the program to macOS platform by command flet build macos --arch arm64, the program runs with an exception:

Traceback (most recent call last):
  File "<string>", line 95, in <module>
  File "<frozen runpy>", line 229, in run_module
  File "<frozen runpy>", line 88, in _run_code
  File "/path.../flet/app/main.py", line 2, in <module>
    import video_thumbnail_grid_maker as maker
  File "/path.../flet/app/video_thumbnail_grid_maker.py", line 1, in <module>
    import cv2
ModuleNotFoundError: No module named 'cv2'

No warning or exception messages appeared in the terminal during the compilation process.

And the environment detail below :

• PyCharm 2024.3.1.1 (Community Edition)
• Python 3.13.1
• Flet 0.26.0
• opencv-python 4.11.0.86
• Flutter 3.27.3

Please help me, thank you!

[FeodorFitsner]

How does your pyproject.toml look like?

[Xuu6770]

How does your pyproject.toml look like?

Here it is, with some minor changes I have made：

[FeodorFitsner]

Add opencv-python to dependencies section of your pyproject.toml.

[Xuu6770]

Add opencv-python to dependencies section of your pyproject.toml.

It worked, thank you! I'd also like to ask if there's any way to make the size of my packaged program smaller?

dependencies = [
  "flet==0.26.0",
  "opencv-python==4.11.0.86",
  "pillow==11.1.0"
]

import flet as ft
import cv2
from PIL import Image, ImageDraw, ImageFont

As you can see, these are the dependencies my program needs, but just these three libraries alone brought the size of my app to 168.5MB (macOS).

[FeodorFitsner]

First, Flet generates "fat" APK for all platforms. AAB is going to be the same size. However, whatever end user is downloading will be 3 times smaller - ~55MB.
Second, I guess it's opencv binaries which are pretty beefy. You can unpack APK (it's zip) and study its contents.